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U1255 code in many Modules

1542 Views 17 Replies 4 Participants Last post by  basscatt
1998 Seville STS, 4.6 engine, 80k miles

I was passing a truck under heavy throttle and the engine died like I turned the key off.
Mountain road on a curve with no power steering and no power brakes...very hairy!

The DTC code U1255 "lost communications" shows on all of the following... DDM , DIM, IPC, RFA, RIM, VTD, MSM. The PCM had no codes. At the same time "service stability system" showed on dash.
The "lost communications" possible causes listed are...
-Loose control module connectors
-Faulty Control Module
-Control modules poor electrical connection
-Control Modules harness open or shorted

The engine will not start (no spark), and there is an electric humming from the back of engine (without key on) that is draining the battery.

Where do I start to solve this? Any help would be greatly appreciated!!
1 - 2 of 18 Posts
There is no power to the fpr. If you hear something at the fpr with key off, that is fuel flowing through the regulator. Fuel flowing works be sympton of the fuel pump stuck on.
. . .and if the fuel pump is running with key off, then the relay is stuck on either due to a failed relay or a failure/short in the signal wire to the relay.
1 - 2 of 18 Posts
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